LOADING  AND  TRANSPORTING 
WESTERN  CANTALOUPES 


By 
A.  W.  McKAY 

Specialist  in  Marketing 


UNITED  STATES  DEPARTMENT  OF  AGRICULTURE 
BUREAU  OF  MARKETS 

CHARLES  J.  BRAND,  Chiei 


Markets  Doc.  10 


Washington,  D.  C. 


June,  1918 


SUMMARY 

OADIJNG  different  styles  of  cantaloupe  packages  together 
J— ^  obstructs  air  circulation  and  seriously  retards  refrig- 
eration. 

Cantaloupe  shipments  loaded  seven  standard  crates  wide 
and  three  high  can  be  cooled  more  easily  and  uniformly  than 
those  loaded  six  crates  wide  and  four  high  at  the  bulkhead. 

Floor  racks  are  an  effective  aid  in  the  refrigeration  of  can- 
taloupe shipments. 

The  ability  of  refrigerator  cars  to  cool  cantaloupe  ship- 
ments quickly  and  maintain  desirable  temperatures  in  transit 
depends  directly  upon  proper  bunker  and  bulkhead  con- 
struction and  upon  the  quantity  and  quality  of  the  insulating 
material  employed  in  their  construction. 

Workmanlike  construction  of  refrigerator  cars,  inspection 
for  defects,  and  the  maintenance  of  the  cars  in  good  repair 
are  essential  for  satisfactory  service. 

Salt  may  be  effectively  employed  to  hasten  the  refrigera- 
tion of  cantaloupe  shipments. 

The  wrapping  of  cantaloupes  serves  to  retard  the  rate  of 
cooling. 

Moving  cantaloupe  cars  with  the  ventilators  open  during 

the  first  night  in  transit  does  not  appear  to  affect  the  refrig- 

•_ 

eration  of  the  melons,  or  their  condition   upon   arrival  at 
market. 


LOADING  AND  TRANSPORTING  WESTERN 
CANTALOUPES 


CONTENTS 


Page 
General  considerations 3 

Effect  of  mixed  loading  on  refrigeration- ...   5 

Temperatures  in  transit 7 

Floor  racks.  ..  ..7 


Page 
Car  construction  and  insulation 10 

The  use  of  salt  as  an  aid  to  refrigeration 12 

Miscellaneous  practices   affecting  refrigera- 
tion... ,.   15 


GENERAL  CONSIDERATIONS 

DURING  the  shipping  seasons  of  1915,  1916,  and  1917,  the  United 
States  Department  of  Agriculture  conducted  investigations  to 
determine  the  transit  temperature  conditions  under  which  western 
cantaloupes  are  forwarded  to  market,  and  the  influence  of  loading 
methods  and  modifications  of  car  construction  in  retarding  or  accel- 
erating refrigeration.  Test  trips  were  made  from  the  Imperial  Valley, 
Gal.,  Turlock,  Gal.,  and  Glendale,  Ariz.  In  each  test,  the  shipments 
under  observation  were  loaded  on  the  same  day  and  the  cars  moved 
in  the  same  train  to  destination.  They  were  accompanied  by  repre- 
sentatives of  the  Department,  who  at  intervals,  approximately  five 
or  six  hours  apart,  secured  a  record  of  the  temperature  of  the  air  and 
melons  at  12  selected  locations  in  each  car.  The  observers  also 
obtained  a  record  of  the  atmospheric  temperature,  and,  in  most 
cases,  of  the  actual  weight  of  the  ice  supplied  each  car.  The  number 
of  cars  in  each  test  varied  from  4  to  13,  the  usual  number  being 
about  8. 

The  temperatures  within  the  cars  were  obtained  by  specially  con- 
structed electrical  thermometers.  These  thermometers  were  con- 
nected by  short  cables  to  a  master  cable.  A  small  portion  of  the 
master  cable,  in  the  form  of  a  flattened  plate,  passed  out  between 
the  door  and  door  frame  to  the  roof  of  the  car.  Thus  no  opening 
was  made  that  would  permit  an  appreciable  influx  of  hot  air.  The 
temperature  readings  were  obtained  from  the  roof  of  the  car.  By 
the  use  of  this  equipment,  it  was  possible  to  obtain  an  accurate  record 
of  temperature  conditions  within  the  cars  without  opening  the  doors 
or  ventilators  at  any  time.  It  was  also  possible  to  obtain  the  tempera- 
ture of  melons  in  crates  at  the  bottom  of  the  load,  and  at  other  points 
where  it  would  have  been  impossible  to  locate  or  read  mercury 
thermometers. 

Every  effort  was  made  to  control  each  shipment  tested,  so  that  it 
differed  from  the  others  in  the  same  test  only  with  regard  to  the 


Loading  and  Transporting  Western  Cantaloupes 


particular  factor  under  investigation.  This  was  accomplished  in  all 
cases,  so  far  as  it  was  possible  under  actual  service  conditions.  The 
effects  of  loading  methods,  car  construction,  and  refrigeration  practices 
on  the  temperature  of  cantaloupes  in  transit  are  presented  graphically 
in  the  illustrations  accompanying  the  text. 

Although  the  investigations  discussed  herein  were  conducted  only 
with  cantaloupes  grown  in  California  and  Arizona,  they  should  prove 
of  interest  to  growers  and  shippers  of  cantaloupes  in  other  sections 
of  the  country.  The  results  presented  are  directly  applicable  to  the 
shipment  of  cantaloupes,  wherever  grown,  which  are  three  days  or 
longer  in  transit. 


Fio.  1. — Diagram  showing  top  layer  temperature*  at  the  bulkhead  and  adjacent  to  the  bracing  in 
cantaloupe  shipment*.  Each  curve  represents  the  average  of  two  care.  Cars  A  and  B  were  loaded 
7  crate*  wide  and  3  crates  high  throughout:  can  C  and  D  were  loaded  6  crnles  wide  throughout  and 
4  cratas  high  in  the  4  stacks  next  to  each  bulkhead.  These  cam  were  in  transit  from  Brawley,  Cal., 
to  Chicago.  III..  June  19  to  25.  1016. 


Loading  and  Transporting  Western  Cantaloupes  5 

EFFECT  OF  MIXED  LOADING  ON  REFRIGERATION 

A  factor  of  great  importance  in  influencing  the  refrigeration  of 
cantaloupes  in  transit,  and  one  which  is  under  the  direct  control  of 
the  shipper,  is  the  method  of  loading  employed,  and  the  care  taken 
to  secure  a  uniformly-spaa  d  load.  One  of  the  greatest  obstacles  to 
rapid  and  uniform  refrigeration  is  the  common  practice  of  mixing 
different  styles  of  packages  in  the  same  load.  The  circulation  of 
cold  air  from  the  ice  bunkers  through  the  load  by  natural  means  is 
necessarily  slow.  If  open  spaces  between  the  rows  of  packages  are 
not  provided,  the  flow  of  cold  air  toward  the  center  of  the  car  is 
checked.  Under  these  conditions,  the  air  rises  toward  the  ceiling  of 
the  car,  and  returns  to  the  ice  bunker  without  completing  its  normal 
circuit,  and  consequently  refrigeration  of  the  crates  in  the  center  of 
the  car  is  retarded  materially. 

Though  mixed  loading  is  the  most  common  cause  of  these  air 
blockades,  careless  loading  or  shifting  of  packages  will  bring  about 
the  same  unfavorable  condition.  Every  effort  should  be  made  to 
load  only  one  style  of  package  in  the  same  end  of  a  car.  If  it  should 
be  necessary  to  load  flats  and  standard  crates  together,  the  flats 
should  be  placed  on  top  layers  or  in  the  stacks  nearest  the  bracing. 

Figure  1  shows  the  temperatures  secured  in  four  cars  of  canta- 
loupes, which  were  included  in  a  test  from  Brawley,  Cal.,  in  1916. 
Two  of  these  cars  were  loaded  7  crates  wide  and  3  high  throughout. 
The  other  two  were  loaded  6  crates  wide  and  4  high,  for  a  distance 
of  4  stacks  from  each  bulkhead.  The  remainder  of  the  load  was  3 
crates  high. 

The  temperature  records,  which  have  been  confirmed  by  later  tests, 
show  that  cantaloupes  four  crates  high  cannot  be  cooled  satisfactorily 
in  the  ordinary  refrigerator  car.  It  will  be  noted  that  the  average 
temperature  of  the  top  layer  crates  at  the  bulkhead  in  cars  loaded  C 
wide  and  4  high  is  higher  than  the  top  layer  temperature  in  the  center 
of  the  cars  loaded  7  wide  and  3  high,  and  considerably  higher  than 
the  top  layer  temperature  at  the  bulkhead  of  these  cars.  The  average 
temperature  at  the  center  of  the  cars  loaded  6  crates  wide  was  lower 
than  the  temperatures  against  the  bulkhead,  owing  to  the  fact  that 
the  melons  were  only  3  crates  high  at  this  point.  It  corresponded 
almost  exactly  with  the  average  top  layer  temperature  at  the  center 
of  the  cars  loaded  7  wide,  and  for  that  reason  has  not  been  included 
in  the  diagram. 


Loading  and  Transporting  Western  Cantaloupes 


Loading  and  Transporting  Western  Cantaloupes  7 

TEMPERATURES  IN  TRANSIT 

Figures  2  to  7  illustrate  graphically  the  temperatures  in  transit 
secured  in  cars  of  cantaloupes,  when  the  cars  vary  in  construction 
and  in  the  refrigeration  methods  employed.  The  six  temperatures 
shown  on  each  chart  are  those  which  are  approximately  representative 
of  conditions  throughout  the  whole  load.  They  were  secured  in 
crates  located  in  the  top  layer  at  the  bulkhead,  the  bottom  layer  at 
the  bulkhead,  the  top  layer  half  way  between  the  bulkhead  and  door 
frame,  the  bottom  layer  half  way  between  the  bulkhead  and  door 
frame,  the  top  layer  next  to  the  bracing,  and  the  bottom  layer  next  to 
the  bracing.  It  will  be  noted  that  the  temperatures  in  these  six 
positions  vary  considerably. 


i^H  10.  LATM.    M4L*  bCIWTH  O»  kO. 


FIG.  3. — Diagram  showing  cantaloupe  temperatures  in  a  car  equipped  with  basket  bunkers,  insu- 
lated bulkheads,  and  floor  racks.  This  car  was  in  transit  from  Brawley,  Cal.,  to  New  York,  N.  Y., 
June  26  to  July  8,  1917. 

FLOOR  RACKS 

Slatted  false  floors,  or  floor  racks,  have  proved  to  be  a  most  effec- 
tive aid  to  refrigeration,  and  have  been  included  as  part  of  the  equip- 
ment of  nearly  all  refrigerator  cars  constructed  since  1916.  As 
permanently  constructed,  the  floor  racks  are  hinged  to  the  car  walls, 
and  may  be  raised  when  the  car  is  cleaned.  The  cross-slats  are 
approximately  4  inches  wide,  and  are  sufficiently  close  together  to 
permit  trucking  over  the  racks.  The  lengthwise  stringers  are  4 
inches  high,  providing  a  clear  4-inch  air  space  under  the  entire  load. 


Loading  and  Transporting  Western  Cantaloupes 


_JL_J I! 1! 3! II 5 X 


Loading  and  Transporting  Western  Cantaloupes 


9 


Figure  2  presents  graphically  the  temperatures  in  an  ordinary 
refrigerator  car,  loaded  7  crates  wide  and  3  high,  shipped  from  Braw- 
ley,  Cal.,  to  New  York  City  in  June,  1917.  Figure  3  shows  the 
temperatures  in  a  car  equipped  with  solid  insulated  bunker  bulk- 
heads and  floor  racks,  shipped  from  Brawley,  Cal.,  to  New  York 
City  at  the  same  time.  It  will  be  noted  that  refrigeration  is  more 


25 


MI^M   110        I-II^M   lUtJ 

LOW   84     LOW    76 


HIGH  KW°  HIGH  104 


LOW  74' 


HIGH   6{£]H!CH   88° 

LOW  77°  UOW  46" 


. 

LOW    5g 


rMCH  84' 
LOW  48° 


LOW   49° 


68*1  HtCH  68* 


LOW   55' 


TEMPERATURES  IN  TRANSIT 

CANTALOUPES.     CALIFORNIA  TO  NEW  YORK,  1917 

3   PLY    INSULATION.     POOR  CONSTRUCTION 
3    PLY   INSOLATION     RtBUILT    JAN.  1917 

THE  CURVES  snow  THE  AVERAGE 'or  ALL   FRUIT 

TEMPERATURES     TAKEN    IN  THE  TOP  LAYER  OF  EACH    CAR. 


85 


2*>DAY  3"°  DAY  V"  DAY  5™  DAY  6™  DAY  7™  DAY  8T 


95 


FIG.  5. — Diagram  showing  the  average  temperatures  of  the  melons  in  the  top  layers  of  the  two  cars 
represented  in  figures  2  and  4. 


10  Loading  and  Transporting  Western  Cantaloupes 


uniform  in  the  car  with  floor  racks,  and  that  cooling  proceeds  more 
rapidly.  This  is  very  noticeable  in  the  temperatures  of  the  top  layer 
crates,  especially  the  one  located  near  the  doorway.  Other  tests 
have  demonstrated  that  the  temperatures  shown  in  these  diagrams 
are  representative  of  the  conditions  obtained  in  cars  of  these  two 
types.  The  additional  cooling  obtained  by  the  use  of  floor  racks  is 
an  important  factor  in  retarding  ripening  and  deterioration.  The 
reduction  of  the  temperatures  of  the  top  layer  is  now  the  chief  problem 
in  transit  refrigeration. 

CAR  CONSTRUCTION  AND 'INSULATION 

The  bunker  and  bulkhead  construction  of  refrigerator  cars  has  an 
important  effect  on  the  refrigeration  obtained  in  transit.  In  the 
ordinary  box  bunker  air  n  culation  is  obstructed  by  the  mass  of  ice, 
and  refrigeration  of  the  shipment  is  retarded  in  consequence.  To 
overcome  this  difficulty,  it  IIMS  been  found  desirable  to  attach  heavy 
wire  screens,  or  perforated  metal  sheets,  to  2-inch  vertical  nailing 
strips,  which  are  secured  to  the  sides  and  ends  of  the  bunker.  This 
so-called  "basket  bunker"  provides  a  clear  2-inch  air  space  on  all 
sides  of  the  ice.  The  advantages  of  this  space  are  obvious. 

A  solid,  insulated  bunker  bulkhead,  with  12  to  14-inch  openings  at 
the  top  and  bottom,  has  been  found  more  effective  than  the  open 
type  of  bulkhead,  when  used  in  conjunction  with  the  wire-basket 
bunker  and  floor  racks.  With  a  bulkhead  of  this  type,  the  air  must 
pass  to  the  bottom  of  the  bunker  and  be  completely  chilled  before  it 
escapes  to  the  body  of  the  car.  In  cars  equipped  with  open  bulk- 
heads, many  local  currents  of  partially-chilled  air  pass  through  the 
bulkheads  at  various  points. 

The  ability  of  refrigerator  cars  to  refrigerate  cantaloupe  shipments 
and  to  maintain  satisfactory  temperatures  in  transit  depends,  also, 
upon  the  quality  and  quantity  of  insulating  material  employed  in 
their  construction.  Tests  have  shown  that  the  minimum  require- 
ments for  the  floors  of  refrigerator  cars  are  2  inches  of  cork,  protected 
from  moisture  by  waterproof  paper,  or  other  waterproofing  material. 
For  the  walls,  2  inches  of  cork,  or  material  which  is  equivalent  to 
cork  in  heat  transmission,  are  necessary,  and  for  the  roof  2^  inches 
of  insulating  material,  equivalent  in  heat  transmission  to  2J-£  inches 
of  cork.  Equally  as  important  as  the  amount  and  quality  of  insulat- 
ing material  employed  is  the  method  of  its  application  to  the  car 
walls,  and  the  attention  paid  to  details  in  the  construction,  rebuilding, 
or  repairing  of  the  cars. 


Loading  and\Transporting  Western  Cantaloupes 


11 


The  importance  of  these  factors  is  illustrated  by  figure  4,  which 
shows  diagrammatically  the  temperatures  obtained  in  a  car  of  can- 
taloupes shipped  from  Brawley  to  New  York  City  in  June,  1917. 
This  car  may  be  compared  with  the  car  represented  in  figure  2.  It 
contained  an  equal  quantity  of  insulating  material  but  was  not  of 
equally  good  construction,  nor  had  jt^been  as  carefully  inspected,  or 


TEMPERATURES  IN  TRANSIT. 

CANTALOUPES,    CALIFORNIA  TO  NEW  YORK,  1917. 
CAR  A  0  3  PLY  INSULATION,     POOR  CONSTRUCTION 

CAR  B    — -o— —    3  PLV  INSULATION.     REBUILT  JAN.  1917 
CARC  •  INSULATED  BULKHEADS.  FLOOR  RACKS.    SALT  ADDED 


TO   THE    ICE  AT  EACH    OF  THE  FIRST    THREE    REICINCS    3    PLY  INSULATION 


TEMPERATURES  OF  THE  MELONS  in  THE  CRATE  LOCATED  AT  THE 

TOP    LAYER,   CENTER    ROW,      SEVENTH  STACK    FROM   THE    BUNKER, 
IN    EACH    CAR. 


PERCENT    SOFT  MELON  SON  TOP 


Jft  1"  DAY    2»DAY 


FIG.  C. — Diagram  showing  the  warmest  temperature  of  the  melons,  and  the  percentage  of  soft  melons 
in  the  top  layers,  in  the  three  cars  represented  in  figures  '2,  4,  and  7. 


12  Loading  and  Transporting  Western  Cantaloupes 

repaired,  when  repairs  were  necessary.  The  temperature  differences 
are  striking,  and  illustrate  the  importance  of  close  attention  to  details 
of  construction  and  repair  of  refrigerator  cars. 

An  average  of  the  top  layer  temperatures  in  these  two  cars  is 
shown  in  figure  5.  The  two  upper  curves  in  figure  6  represent  the 
top  layer  temperature  next  to  the  bracing  in  the  same  cars.  Attention 
is  called  to  the  heavy  black  lines  in  figure  6,  representing  the  per- 
centage of  soft  cantaloupes  in  the  top  layer  of  each  of  these  cars  when 
inspected  at  New  York.  Gar  A,  it  will  be  seen,  arrived  with  86  per 
cent  soft,  or  all  crates,  except  those  immediately  against  the  two 
bulkheads.  In  Car  B,  14.3  per  cent  of  the  melons  in  the  top  layer 
were  soft. 

THE  USE  OF  SALT  AS  AN  AID  TO  REFRIGERATION 

The  refrigeration  of  perishable  shipments  is  effected  by  the  melting 
of  ice  in  the  bunkers  of  the  cars.  If  no  ice  is  melted  no  cooling  results. 
The  rather  common  belief  that  the  presence  of  ice  in  itself  constitutes 
a  source  of  refrigeration  is  not  correct.  The  actual  condition  is 
comparable  to  the  burning  of  coal  to  produce  heat.  It  is  the  coal 
that  burns  which  produces  heat;  the  mere  presence  of  coal  cannot 
affect  temperature  conditions. 

After  the  ice  is  melted,  the  resulting  cold  water  has  very  little 
cooling  effect  in  comparison  with  that  of  the  ice  in  melting.  One 
pound  of  ice  will  take  up  144  heat  units  during  the  melting  process, 
whereas  the  pound  of  water  formed  from  the  same  ice  will  take  up 
only  1  heat  unit  for  each  degree  which  it  is  warmed. 

Ice  made  from  pure  water  melts  at  exactly  32°  Fahrenheit.  When 
ice  is  melting  in  contact  with  air,  its  temperature  must  be  32°.  If 
it  were  colder  it  would  not  be  melting.  It  cannot  become  warmer 
until  after  it  is  melted.  When,  however,  salt  is  mixed  with  crushed 
ice,  a  mixture  is  formed  which  melts  at  a  temperature  lower  than  32°. 
The  temperature  at  which  it  melts  depends  on  the  percentage  of  salt 
and  the  thoroughness  with  which  the  salt  is  mixed  with  the  ice.  If 
the  percentage  of  salt  is  increased,  up  to  a  certain  limit,  the  melting 
temperature  of  the  mixture  is  lowered.  Twenty-five  per  cent  salt 
and  75  per  cent  finely-crushed  ice,  thoroughly  mixed,  melts  at  about 
3  or  4°  below  zero  F.  This  is  the  lowest  temperature  which  can  be 
obtained  with  salt  and  ice.  If  still  more  salt  is  added,  that  is,  if  the 
mixture  contains  more  than  25  per  cent  salt,  the  melting  temperature 
will  not  be  as  low. 


Loading  and  Transporting  Western  Cantaloupes 


13 


-2 


14  Loading  and  Transporting  Western  Cantaloupes 

In  an  ice  and  salt  mixture,  the  ice  melts  more  rapidly  than  when 
ice  alone  is  present,  on  account  of  the  lower  temperature  of  the 
mixture.  Consequently,  heat  is  taken  up  more  rapidly  from  the  air 
and  produce  within  the  car,  and  both  are  cooled  to  a  lower  tempera- 
ture than  is  possible  by  the  use  of  ice  alone. 

Several  experiments  have  been  made  to  determine  the  additional 
cooling  obtained  by  salting  the  ice  in  the  bunkers  of  cars  of  canta- 
loupes immediately  after  loading.  It  has  been  determined  that  cool- 
ing is  considerably  hastened  by  this  practice.  When  salt  is  used  it 
should  be  added  to  the  ice  immediately  after  the  car  is  loaded.  The 
ice  at  the  top  of  the  bunker  should  be  broken  up  into  small  pieces 
with  an  ice  pick,  and  the  salt  applied  on  top  of  the  ice.  Coarse  salt. 
No.  2  or  larger,  is  preferable.  When  the  temperature  of  the  melons 
is  80°  F.,  or  higher,  10  per  cent  of  salt,  approximately  500  pounds 
to  each  bunker,  may  be  safely  added  at  the  first  application.  At  the 
first  icing  station  100  to  150  pounds  of  salt  may  be  applied  to  each 
bunker.  If  the  temperature  of  the  melons  is  below  80°  F.,  the  quan- 
tity of  salt  should  be  reduced,  not  more  than  5  to  8  per  cent  being 
added  at  the  first  application,  according  to  temperature  conditions. 

Salt  should  never  be  added  to  the  ice,  except  in  cars  equipped  with 
floor  racks,  solid,  insulated  bunker  bulkheads,  and  basket  bunkers 
which  provide  a  2-inch  air  space  around  the  ice.  On  account  of  the 
obstructions  to  air  circulation  in  the  ordinary  refrigerator  car,  the 
use  of  salt  in  a  car  of  this  type  merely  serves  to  chill  or  freeze  the 
melons  at  the  floor  of  the  car  near  the  bulkhead  without  in  any  way 
hastening  the  cooling  in  the  warmer  portions  of  the  load.  With  the 
improved  construction  already  described,  however,  air  circulation  is 
continuous  and  unobstructed,  and  there  is  no  banking  of  cold  air 
against  the  crates  close  to  the  bulkhead. 

Figure  6  shows  the  top  layer  temperature  at  the  bracing  in  a  salted 
car  (Car  C)  as  compared  with  the  temperature  in  the  same  location 
in  two  cars  already  described.  This  is  usually  the  warmest  portion 
of  the  load,  and  it  will  be  seen  that  refrigeration  is  considerably 
hastened  and  the  temperature  materially  lowered  by  the  use  of  salt 
and  the  improved  construction  of  the  salted  car.  It  will  be  observed, 
also,  that  9.8  per  cent  of  the  melons  in  the  top  layer  of  the  salted 
car  were  considered  "soft"  from  a  marketing  standpoint  upon  arrival 
at  destination,  as  compared  with  86.0  in  Car  A,  and  14.3  per  cent 
in  Car  B. 


DC  SOUTHERN  REGIONAL  LIBRARY  FACILITY 


A     001  073  700 

Loading  and  Transporting  Western  Cantaloupes 


MISCELLANEOUS  PRACTICES  AFFECTING  REFRIGERATION 

The  practice  of  opening  either  the  front  or  rear  ventilators  of  a 
refrigerator  car  during  the  first  night  the  car  is  in  transit  has  some 
adherents  among  cantaloupe  shippers.  A  few  tests  have  been  made 
of  the  value  of  this  practice,  but  the  results  obtained  are  inconclusive. 


FIG.  8. — Diagram  illustrating  the  effect  of  wrapping  cantaloupes  upon  temperatures  in  transit.  The 
melons  in  car  A  were  wrapped;  those  in  car  B  were  not  wrapped.  These  cars  were  in  transit  from 
Brawley,  Cal.f  to  Chicago,  111.,  June  19  to  25,  1916. 

It  can  be  definitely  stated  that  refrigeration  is  not  hastened  by  this 
practice;  on  the  other  hand,  the  admission  of  outside  air  during  the 
night  does  not  seem  to  raise  the  cantaloupe  temperatures  or  retard 
refrigeration.  An  average  of  400  or  500  additional  pounds  of  ice  is 
melted  in  each  car  when  the  ventilators  are  open. 

It  is  claimed  that  cantaloupes  arrive  at  market  in  a  firmer  con- 
dition and  that  fewer  yellow  melons  develop  when  they  are  shipped 


16  Loading  and  Transporting  Western  Cantaloupes 


in  cars  with  the  ventilators  open  the  first  night.     No  conclusive  data 
have  been  obtained  either  proving  or  disproving  this  claim. 

The  practice  of  wrapping  cantaloupes  serves  to  some  extent  to 
retard  refrigeration.1  The  paper  fulfills  the  function  of  an  insulating 
covering,  and  prevents  the  transmission  of  the  field  heat  of  the  melons. 
In  addition,  the  paper  wraps  tend  to  obstruct  the  circulation  of  cold 
air  around  and  through  the  crates.  This  is  illustrated  in  figure  8, 
which  presents  the  average  of  the  top  and  bottom  layer  tempera- 
tures of  two  cars  of  similar  construction,  loaded  similarly,  with  the 
exception  that  the  melons  in  one  were  wrapped  and  those  in  the  other 
were  not  wrapped.  The  differences  shown  are  representative  of  the 
retardation  of  refrigeration  which  may  be  expected  when  cantaloupes 
are  wrapped  for  shipment. 

1  KIM.  h.-r.  G.  L..  and  Nelson.  A.  E.      More  care  is   needed   in  handling  Western  cantaloupes 
Li.ited  States  Department  of  Agriculture,  Markets  Document  9,  1018. 


